| anaesthetic depth | The degree of central nervous system depression produced by a general anaesthetic agent; a function of potency of the anaesthetic and the concentration in which it is administered. (05 Mar 2000) |
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| depth | Distance from the surface downward. (05 Mar 2000) |
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| depth compensation | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| depth dose | The dose of radiation at a distance beneath the surface, including secondary radiation or scatter, in proportion to the dose at the surface. (05 Mar 2000) |
| depth of field | <microscopy> The depth or thickness of the object space that is simultaneously in acceptable focus. The distance between the closest and farthest objects in focus within a scene as viewed by a lens at a particular focus and with given settings. The depth of field varies with the focal length of the lens and its f-stop setting or numerical aperture, and the wavelength of light. Depth of fields only a small fraction of a micrometre can be achieved at 546 nm with microscope lenses of N.A. Greater than 0.9. (05 Aug 1998) |
| depth of focus | <microscopy> The depth or thickness of the image space that is simultaneously in acceptable focus. The range of distances between a lens and image plane (target in the video pickup device) for which the image formed by the lens at a given setting is clearly focused. With a high-numerical aperture microscope objective, the depth of field is very shallow, but the depth of focus can be quite deep and reach several millimetres. (05 Aug 1998) |
| depth perception | Perception of three-dimensionality. (12 Dec 1998) |
| depth psychology | The psychology of the unconscious, especially in contrast with older (19th century) academic psychology dealing only with conscious mentation; sometimes used synonymously with psychoanalysis. (05 Mar 2000) |
| depth recording | Study of subcortical cerebral electrical activity after placing electrodes in these areas. (05 Mar 2000) |
| field depth | <microscopy> The thickness of the object space within which objects focused by a lens will all appear in good simultaneous focus. Penetration is a synonym. (05 Aug 1998) |
| focal depth | Depth of focus, the greatest distance through which an object point can be moved while maintaining a clear image. Synonym: penetration. (05 Mar 2000) |
| anaesthetic | 1. <neurology> Pertaining to, characterised by or producing anaesthesia. 2. <pharmacology> A drug or agent that is used to produce partial loss of feeling or sensation of pain. (14 May 1997) |
| anaesthetic circuit | Equipment used during inhalation anaesthesia to regulate concentrations of inhaled gases; includes a reservoir bag and usually directional valves, breathing tubes, and a carbon dioxide absorber. (05 Mar 2000) |
| anaesthetic, epidural | An anaesthetic injected into the epidural space surrounding the fluid-filled sac (the dura) around the spine which partially numbs the abdomen and legs. (12 Dec 1998) |
| anaesthetic ether | General designation for many ether's. (05 Mar 2000) |
| anaesthetic gas | A gas or a liquid with sufficient vapor pressure to produce general anaesthesia when breathed. (05 Mar 2000) |